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rain making debate Rainmaking technology funded by the Australian government has already been given the thumbs down by international scientists, says an adviser to the World Meteorological Organization.

But proponents of the technology say the criticism is unjust.

Dr Roelof Bruintjes, a US-based researcher who advises the World Meteorological Organization (WMO) on rainfall enhancement, was commenting on technology soon to be tested in Queensland by the Australian Rain Corporation.

The Sydney-based company, which was recently allocated A$10 million from the Australian Government Water Fund, hopes to use forthcoming trials to show its technology can bring rain.

The technology is being tested to see if it can make new rain clouds from blue skies by generating ions in the atmosphere.

This is very different from existing rainmaking technology, which relies on seeding existing clouds, and has been carried out for decades in Tasmania and the Snowy Mountains.

Some Australian experts have already publicly said they are sceptical of the new ionisation technology and Bruintjes agrees.

"I don't think it's money well spent to be honest with you. As far as I'm concerned it's physically not possible," he says.

"Nobody can make or chase away a cloud. Nobody can make rain out of nothing."

Making clouds from scratch?

Scientists involved in testing the Australian Rain Corporation technology, including Professor Jürg Keller of the University of Queensland, say the ionisation system uses a ground-based device to attract water molecules.

These then condense, generating heat that, in turn, triggers an up-draft of the kind that occurs when clouds form naturally.

But Bruintjes, a cloud physicist at the National Center for Atmospheric Research in Boulder Colorado, says WMO experts have already warned against using such ionisation techniques because they are not based on accepted scientific principles.

Bruintjes says while it's possible to ionise atmospheric particles, it is not possible to modify the thermodynamic structure of the atmosphere and so there is no current credible theory to support the idea.

He also says evaluations of the technology in the United Arab Emirates and Mexico have shown it is not useful in enhancing rainfall.

Bruintjes does not understand why Australia has embraced the technology.

"Any country that is in a severe drought is desperate to use any type of technology and maybe this is what has happened in Australia," he says.

If it works, hang the mechanism

Queanbeyan-based sustainability consultant Andrew Campbell, is advising the Australian Rain Corporation on the Queensland trials.

He says it is prudent to investigate whether the technology works in Australian conditions, even if scientists don't understand how it works.

"From a water policy perspective, the much more important question is whether or not this technology enhances rainfall," says Campbell, former chief executive officer of Land and Water Australia.

"If it does we can analyse the mechanisms at our leisure. If it doesn't then that's a completely academic exercise."

Campbell says he is not aware of any prior evaluation of the technology Australian Rain Corporation will be trialling.

But Bruintjes is adamant the technology is the same Russian-developed system that has been promoted over many years by various companies around the world, and which the WMO has warned against.

Competitors?

Bruintjes is currently in Australia advising the Queensland government on cloud seeding.

Campbell says criticism of the competing ionisation technology is not justified.

"It's understandable that people involved in cloud seeding are concerned about a competitive technology," he says.

"But until it is properly scientifically evaluated, claims either for or against aren't credible."

Bruintjes agrees it's urgent to investigate rain enhancement technologies but says there are better ways to spend the money.

He says one problem is that it's very difficult to determine the success of any rain enhancement technology because of natural variation in rainfall.

Bruintjes says it's important to develop a better understanding of how rain forms in clouds, and how technologies with known physical mechanisms can manipulate this.

"We need to focus on understanding rather than just going out blindly testing technology we don't understand," he says.